For seawater desalination technology, energy conservation and the development of practical method is to use an evaporative enrichment equipment – VVCC (that is, the vacuum and evaporation, condensation, aggregation). The device adopts the heat pump, stainless steel welded pipe can use evaporation and transform it into heat energy supply system, so as to realize the energy conservation. And if cooperate with various technologies from concentrate recovery of valuable materials, and coagulation shrink as the pure water available. Such a system is indispensable to circular society, and stainless steel in every part of the device has played an important role.Cr formation of passive film of stainless steel welded pipe for nitric acid (HN03) show a significant that oxidizing acid corrosion resistance, but the sulfuric acid (- H2SO4) and hydrochloric acid (HC1) that non oxidizing acid, its poor corrosion resistance. So the joining of 8% or more Ni to improve on non oxidizing acid corrosion resistance. Stainless steel welded pipe can also adapt to outdoor and damp environment, processing is suitable for the production of various liquid concentration plant.Stainless steel have been used in the standard concentration device, used in the evaporation tank, the pipe, heat pump and other stainless steel material to occupy more than half. Required features, the first is to maximize its corrosion resistance, stainless steel welded pipe, especially the pipe, heat pump, such as corrosion, will cause a sharp negative impacts. Therefore, choose carefully before the material to the practical solution corrosion test is necessary.SUS304 steel should be used in general, the evaporation tank, while the pipe using SUS316L steel.In short, the use of the heat-pump principle VVCC evaporation concentration device, can greatly reduce the flow of the seawater desalination cost. Stainless steel welded pipe using the steam enrichment process, but also can significantly reduce CO2 emissions. In this, has played an important role in the use of stainless steel.Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)